Hand And Finger Muscle Problems

I am a 33 yr old female, I am of normal weight, I work out 3-4 times per week w/ body sculpting and fat burning cardio, I eat right most of the time, I stay away from simple carbs, sugars, and salts, and eat allot of seafood, chicken, veggies, and complex carbs, so I feel like I am pretty healthy. About a year ago I noticed my hands and fingers beginning to cramp up. When I play piano or grip something a certain way, my muscles lock up and I can barely move my fingers. It has gotten worse over the last 6 months. The only medical problem I am aware of is a low iron level, I thought between that and the cold weather might be the problem. I have been taking iron pills and vitamins for the last few weeks, but the symptoms are not getting any better. I am adopted, so I do not know my medical history. I am about to go to my family phys about this but thought I would get some on line advise to prepare myself for the possible diagnosis, I am afraid it is serious and am scared. Any help would be much appreciated!!

Sincerely,

suzanne